Sanders, Walter R. (1922). Ice Delivery. Chicago: Nickerson & Collins. pp. 170–172.
gmuender-tagespost.de
"Ein PS für 160 Blumenkübel" [One horsepower for 160 flower pots]. Gmünder Tagespost (in German). July 31, 2015. Archived from the original on December 11, 2019. Retrieved February 25, 2022.
"Twenty Mule Teams". Death Valley National Park. National Park Service. Retrieved February 6, 2013.
openlibrary.org
Smith, D.J.M. (1988). A Dictionary of Horse Drawn Vehicles. J. A. Allen & Co. Ltd. ISBN0851314686. OL11597864M.
Stratton, Ezra M. (1878). The World on Wheels; or, Carriages, with their Historical Associations from the Earliest to the Present Time, Including a Selection from the American Centennial Exhibition. New York: The author. OCLC3570369. OL7004294M.
Burt, Olive W. (1962). John Wanamaker: Boy Merchant. New York: Bobbs-Merrill. p. 62. OL5855211M.
"Ein PS für 160 Blumenkübel" [One horsepower for 160 flower pots]. Gmünder Tagespost (in German). July 31, 2015. Archived from the original on December 11, 2019. Retrieved February 25, 2022.
Stratton, Ezra M. (1878). The World on Wheels; or, Carriages, with their Historical Associations from the Earliest to the Present Time, Including a Selection from the American Centennial Exhibition. New York: The author. OCLC3570369. OL7004294M.